Conditional analysis near strong shear layers in DNS of isotropic turbulence at high Reynolds number

Takashi Ishihara, Julian C.R. Hunt, Yukio Kaneda

Research output: Contribution to journalConference article

3 Citations (Scopus)

Abstract

Data analysis of high resolution DNS of isotropic turbulence with the Taylor scale Reynolds number Rλ = 1131 shows that there are thin shear layers consisting of a cluster of strong vortex tubes with typical diameter of order 10η, where η is the Kolmogorov length scale. The widths of the layers are of the order of the Taylor micro length scale. According to the analysis of one of the layers, coarse grained vorticity in the layer are aligned approximately in the plane of the layer so that there is a net mean shear across the layer with a mean velocity jump of the order of the root-mean-square of the fluctuating velocity, and energy dissipation averaged over the layer is larger than ten times the average over the whole flow. The mean and the standard deviation of the energy transfer T(x, κ) from scales larger than 1/κ to scales smaller than 1/κ at position x are largest within the layers (where the most intense vortices and dissipation occur), but are also large just outside the layers (where viscous stresses are weak), by comparison with the average values of T over the whole region. The DNS data are consistent with exterior fluctuation being damped/filtered at the interface of the layer and then selectively amplified within the layer.

Original languageEnglish
Article number042004
JournalJournal of Physics: Conference Series
Volume318
Issue numberSECTION 4
DOIs
Publication statusPublished - Jan 1 2011
Externally publishedYes
Event13th European Turbulence Conference, ETC13 - Warsaw, Poland
Duration: Sep 12 2011Sep 15 2011

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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